org.commonjava.maven.galley.io.checksum.AbstractChecksumGenerator.java Source code

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Here is the source code for org.commonjava.maven.galley.io.checksum.AbstractChecksumGenerator.java

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/**
 * Copyright (C) 2013 Red Hat, Inc. (jdcasey@commonjava.org)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.commonjava.maven.galley.io.checksum;

import org.apache.commons.io.IOUtils;
import org.commonjava.maven.galley.model.Transfer;
import org.commonjava.maven.galley.model.TransferOperation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import static org.apache.commons.codec.binary.Hex.encodeHexString;

public abstract class AbstractChecksumGenerator {

    protected final Logger logger = LoggerFactory.getLogger(getClass());

    private final MessageDigest digester;

    private final String checksumExtension;

    private ContentDigest digestType;

    private final boolean writeChecksumFile;

    private final Transfer checksumTransfer;

    private String digestHex;

    protected AbstractChecksumGenerator(final Transfer transfer, final String checksumExtension,
            final ContentDigest type, final boolean writeChecksumFile) throws IOException {
        this.checksumExtension = checksumExtension;
        digestType = type;
        this.writeChecksumFile = writeChecksumFile;
        try {
            digester = MessageDigest.getInstance(digestType.digestName());
        } catch (final NoSuchAlgorithmException e) {
            throw new IOException("Cannot get MessageDigest for checksum type: '" + type + "': " + e.getMessage(),
                    e);
        }

        if (writeChecksumFile) {
            logger.debug("Getting checksum transfer for: {}", transfer);
            this.checksumTransfer = getChecksumFile(transfer);
            logger.debug("Locking checksum file: {}", checksumTransfer);
            this.checksumTransfer.lockWrite();
        } else {
            this.checksumTransfer = null;
        }
    }

    public final void update(final byte[] data) {
        digester.update(data);
    }

    public final void update(final byte data) {
        digester.update(data);
    }

    public final void write() throws IOException {
        if (!writeChecksumFile) {
            return;
        }

        logger.info("Writing {} file: {}", checksumExtension, checksumTransfer);

        PrintStream out = null;
        OutputStream stream = null;
        try {
            stream = checksumTransfer.openOutputStream(TransferOperation.GENERATE);
            out = new PrintStream(stream);
            out.print(getDigestHex());
        } finally {
            IOUtils.closeQuietly(out);
            IOUtils.closeQuietly(stream);
        }
    }

    public synchronized String getDigestHex() {
        if (digestHex == null) {
            digestHex = encodeHexString(digester.digest());
        }
        return digestHex;
    }

    public final void delete() throws IOException {
        if (checksumTransfer.exists()) {
            checksumTransfer.delete();
            checksumTransfer.unlock();
        }
    }

    private Transfer getChecksumFile(final Transfer transfer) {
        return transfer.getSiblingMeta(checksumExtension);
    }

    public ContentDigest getDigestType() {
        return digestType;
    }
}